About this blog

I'm a well-known mainframe performance guy, with almost 30 years of experience helping customers manage systems. I also dabble in lots of other technology. I've sought to widen the Performance role, incorporating aspects of infrastructural architecture.

Tags

Recent tweets

Find us on Facebook

Over the years I’ve written emails with data collection requirements dozens of times, with varying degrees of clarity. It would be better, wouldn’t it, to write it once. I don’t think I can get out of the business of writing such emails entirely but here’s a goodly chunk of it.
Another thing that struck me is that the value of some types of data has increased... [More]

You wouldn’t put all your eggs in one basket, CICSwise, would you?
A naive reading of the CICS TS 5.1 announcement materials might lead you to suppose you could .
This post is about thinking about your CICS region portfolio in the light of this announcement.
While every CICS release introduces capabilities that makes it worthwhile to review your region portfolio,
5.1 majors on... [More]

As you will’ve seen in
WLM Response Time Distribution Reporting With RMF
I’ve been thinking about WLM Response Time goals quite a bit recently.
And this post continues the train of thought.
It’s very easy to think of WLM Service Classes as being self contained.
For many that’s true - and only their own performance numbers need to be considered for us to... [More]

If you’re running a workload with WLM Percentile Response Time goals
take a look at the RMF Service Class Period Response Time Goal Attainment instrumentation.
It’s in the Workload Activity Report but this post is about using the raw data to tell the
story better than a single snapshot (or long-term “munging”) can.
(An example of a percentile response time goal is “90% of transactions must... [More]

It's been almost four years since I wrote DB2 Data Sharing and XCF Job Name .
It mostly stands the test of time but there are a couple of things I want to bring up.
I was in the DB2 Development lab a couple of days ago, talking with a couple of developer friends about DB2 Data Sharing and XCF.
They know DB2 Data Sharing and IRLM much better than I do but XCF not so much.
(It's probable that... [More]

There was a time before blogging and what I'm about to talk about is something I used to explain quite often back in those days.
Reminded by a current customer situation - and needing to explain it again - I thought it time to do it this way.
(Here I'm presenting a simplified view, but one that covers the salient features that might help you.)
The CICS / DB2 Connection code provides a... [More]

About a year ago I posted: A Small Step For RMF, A Giant Leap For Self-Documenting Systems .
A year on I've encountered some customer data that's made me go "huh?", related to this.
In the referenced post I mentioned R744FLPN, the Coupling Facility's LPAR Number. For the first time I've seen data where the match - with SMF 70 Logical Partition Number (in Logical Partition Section)... [More]

Hackday X was good clean fun yesterday - though I think it deserves more than one kiss.
Seriously, for once I think I have a hack that actually worked - at least up to a point.
I called my entry "z/OS Batch Analytics Baby Steps" and I think that's about right.
My purpose in taking part in successive Hackdays has been more to participate rather than to win any prizes, and to wave the flag a... [More]

Round about now you'd be expecting posts to be geared towards the recent zEC12 announcement, or perhaps CICS TS 5.1 or the DB2 11 Preview, or IDAA V3.
So what this post is about will probably have slipped by unnoticed.
After all you don't spend all your time looking for obscure New Function APARs, do you?
But I think some of you will find this one of value, or at least quite interesting.
... [More]

This was originally going to be a different post about VSAM's SMF
64 record, based on a customer situation. But it's morphed into
something else: A round up of "recent" enhancements to the SMF 64
record. "Recent"
is a nice euphemism: Some of these enhancements are 15 years old.
But let's start the story at (or at any rate nearer to) the beginning... Back
in the... [More]

I've written extensively in the past about what you can glean about batch suites from SMF, most notably SMF Type 30.
While I don't believe SMF alone can give you the full dependency network (complete with validation) I've just added some analysis to my code that gets me a little closer. As you're probably never going to run my code the bit that would be interesting is the kind of inferences... [More]

This post is about unusual ways of using the SMF 30 Usage Data information, some of which you're certain to want if you're managing z/OS systems' performance.
A long time ago I noticed character strings in SMF 30 records that looked like product names. (As is my wont I was looking at the raw Type 30 records for a different purpose and spotted them.)
Some time later I figured out these were... [More]

I can tell when a CICS region came up - without looking at CICS-specific instrumentation. What's more I can repeat the "trick" for any of MQ, DB2, IMS, etc - and so can you . I've just started work on a new piece of reporting. I'll call it "raddrspc" as that's the name of the REXX EXEC that I'm writing. It's about address spaces - most notably long-running ones. In the... [More]

As previously discussed I'm often in a situation of trying to make sense of a set of job-related SMF data. Even though it may be your own installation's data, you're probably confronted with what I like to call “a journey of discovery” occasionally, too.
I'm always looking for what I can discern from the data. 1 And, when confronted with a set of data about batch jobs, I go into overdrive.
... [More]

You'd think it would be pretty simple to draw a line. Right?
This post discusses an enhancement I'd like to make to my current reporting - and I'm pretty sure that technically I can do it. The question is whether I should .
Consider my current "Memory by address space within Service Class" graph. Here's a sample:
And here's what I think I might like it to look like:
... [More]

I was lucky enough to be in Silicon Valley Lab for DB2 BootCamp last week. There I ran into a DB2 developer I've worked very successfully with in the past - John Tobler.
(He's the guy I look to for questions and issues with DB2 SMF data.)
We had a good discussion about something I'd personally like to see in DB2 Accounting Trace - more WLM information - and this post is as a result of this... [More]

This is the post I was going to write before the discussion that led to CICS VSAM Buffering arose. It's about getting more insight into how WLM is set up and performing than RMF Workload Activity Report data alone allows. I recognise some of this can be done with the WLM policy in hand. But this is about an SMF-based approach. (The piece you can't do with SMF is discerning the WLM classification... [More]

Four score and seven years ago (or so it seems) the Washington Systems Center published a set of mainframe Data-In-Memory studies. These were conducted by performance teams in various IBM labs and were quite instructive and inspiring. I wish I could find the form number (and a fortiori a PDF version) for this book. Anyone? Even hardcopy would be really nice. The reason I mention this is because... [More]

As I said in this post I recently came across the need to handle Unicode when processing DB2 Accounting Trace (SMF 101). I was astonished not to have run into it before in all my many sets of customer data. So I had two things to do: Understand the circumstances under which it happens - which isn't just "be on Version 8 and it will happen automatically." and Figure out how to handle... [More]

In my experience there are two kinds of CICS installations: Those that take CICS down at night - to run the Batch - and those that don't.
There is a loose correlation between what the data manager is and which approach is taken: VSAM-based CICS applications tend to be less 24x7 than DB2 ones, though it's not that clear cut.
This post is about how you (really I) might glean how you... [More]